This systematic review and meta-analysis compared outcomes from partial breast irradiation (PBI) and whole breast irradiation (WBI) using data from >17,000 patients with early stage breast cancer enrolled in 14 randomized trials and 6 observational studies. Overall, it found no significant difference in the risk of ipsilateral breast tumor recurrence with PBI compared to WBI at both 5 and 10 years. However, when it came to specific types of PBI, intraoperative PBI had a significantly higher risk of IBTR at 5 and 10 years. Finally, toxicity was significantly lower after PBI. | Shumway, JNCI 2023
